Thanks for the offer Chuck. I will let you know if I come up with an engine that needs the cross reference. I talked to a MB person locally and he says he "upgrades" the 380's all the time with 420 conversions. He says you simply swap out the entire intake system from the 380 to the 420. Of course he had a 420 he wanted to sell me, so he had an interest in pushing the swap. I think if I don't allow myself to get in a hurry on this project it will turn out well. Again thanks.
It turns out that my engine is in fact a double row chain